Basis of Presentation and Summary of Significant Accounting Policies - Capitalized software (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|---|
Sep. 30, 2021 |
Sep. 30, 2020 |
Sep. 30, 2021 |
Sep. 30, 2020 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Finite-Lived Intangible Assets [Line Items] | |||||||
| Amortization expense | $ 4.6 | $ 4.4 | $ 13.5 | $ 13.4 | $ 17.9 | $ 17.1 | $ 15.6 |
| Capitalized internal-use software | |||||||
| Finite-Lived Intangible Assets [Line Items] | |||||||
| Estimated useful life | 3 years | ||||||
| Capitalized assets | $ 5.2 | 3.1 | |||||
| Amortization expense | $ 1.4 | $ 0.4 | |||||
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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Details
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